Microwave display shows H0 or HO and the unit will not start; often associated with child lock or safety lock.

Safety: No internal repair is usually needed for this condition.

Steps to clear:

• 1. Check user manual: On many Tower microwaves, H0/HO indicates the child lock is active.
• 2. Common unlock method: Press and hold the Stop/Cancel button for 3–5 seconds until the lock icon or H0 disappears. On some models, press and hold the 0 or Clock button instead.
• 3. Power reset: If the lock will not clear, unplug the microwave for 5 minutes, then plug back in and try the unlock sequence again.
• 4. Check for stuck keys: Press each keypad button firmly and ensure none are physically stuck or unresponsive.

Note: If H0 persists and the keypad appears faulty, the membrane keypad or control PCB may require replacement.